1. Field of the Invention
This invention relates to the field of re-entry vehicles and, in particular, to an improved multilobe fuel tank for a lifting body re-entry vehicle.
2. Description of Related Art
With the increased desire to efficiently employ a lifting body re-entry vehicle in earth to orbit and return, it has been necessary to design configurations of such a vehicle which optimize the parameters of reentry, such as heat control and maneuverability. In addition, since it is desired to efficiently deliver payloads to orbit and return the vehicle to earth, thus providing an desired payload weight to orbit, it is desired to provide a fuel tank which can optimize the amount of fuel carried inboard of the vehicle, i.e. a single stage design, and have the structural integrity necessary to withstand the stresses of liftoff, maneuvering and landing. An example of such a tank configuration is provided in U.S. Pat. No. 5,395,072, entitled Propellant Tank Conformal Lifting Body Spacecraft. In such patent, the tank, which consists in general of three overlapping elongated cones, has a cross-section which is defined by three constant radius intersecting circles to conform to an afterbody portion of the vehicle which is conically shaped and has radii which vary linearly with length. While this configuration allows a tank to be integrated with a limited range of vehicle envelopes, it does not efficiently pack the required tank volume inside a wide variety of lifting body re-entry vehicle designs and thereby makes such vehicles larger and heavier.
Thus, it is a primary object of the present invention to provide an improved fuel tank for a lifting body re-entry vehicle.
It is another object of the present invention to provide an improved fuel tank for a lifting body re-entry vehicle that is highly volumetric efficient.
It is a further object of the present invention to provide an improved fuel tank for a lifting body re-entry vehicle that is conformal to the vehicle shape and maintains a high packing efficiency.
It is still another object of the present invention to provide an improved fuel tank for a lifting body re-entry vehicle that is conformal to the vehicle shape and has tank walls that have hoop tension stresses for a lightweight design.